( RIA Novosti ) - At least four people were killed and six injured when 35 cars and trucks collided on a bridge 113 kilometers ( 70 miles) south of Moscow Tuesday morning, a police official said. The car pileup occurred at about 8:00 a.m. Moscow time (4:00 a.m. GMT) on the Kashirskoye highway's bridge across the Oka river, police said. Traffic on the road has been blocked. Preliminary reports said the accident occurred because of poor visibility caused by fog.